4l60e doesn't shift from D2 to D3 at wot
#1
4l60e doesn't shift from D2 to D3 at wot
Hi,
I am a new tranny tech, a customer of mine came to me with transmission that doesn't shift from D2 to D3 at wot and very harsh shifting all the time at all gears and ranges. i dismantled the transmission and found the following:
burned band and damaged input drum
wrong servo pin (broken and fixed by welding which made it longer)
very tight clearance of 3-4 clutch pack
oil PR tested and found leaking badly, replaced with over size and leak was fixed (tested by sonnax vacuum test kit)
VB was tested and found okay
manual lever switch was found faulty and replaced with new one.
the tranny was fixed, after testing the harsh shifting issue is resolved but the wot issue is not resolved
please advice if you know the cause.....
Thanks,
I am a new tranny tech, a customer of mine came to me with transmission that doesn't shift from D2 to D3 at wot and very harsh shifting all the time at all gears and ranges. i dismantled the transmission and found the following:
burned band and damaged input drum
wrong servo pin (broken and fixed by welding which made it longer)
very tight clearance of 3-4 clutch pack
oil PR tested and found leaking badly, replaced with over size and leak was fixed (tested by sonnax vacuum test kit)
VB was tested and found okay
manual lever switch was found faulty and replaced with new one.
the tranny was fixed, after testing the harsh shifting issue is resolved but the wot issue is not resolved
please advice if you know the cause.....
Thanks,
#2
TECH Junkie
What vehicle is this in?
If going from a stock build to performance build could be a tuning issue.
Does it eventually shift after bouncing off the limiter?
If going from a stock build to performance build could be a tuning issue.
Does it eventually shift after bouncing off the limiter?
#3
TECH Junkie
The 2 - 3 and the 3 - 2 shifts in this unit are "syncronous shifts" and require proper clearances/ timings of the corresponding band and clutch assembly.
Should the 2 - 4 Band be too lose and the 3 - 4 clutch be too tight; the 2 - 3 up-shift will not occur properly (basically what you found).
Also should the 2 - 4 band be too tight and the 3 - 4 clutch be too lose... the 2 - 3 shift will still not occur properly.
Incorrect timing of this shift will either cause a down-shift into first instead of third; or up-shift into fourth instead of third, before eventually going into third gear.
This is going to go against what the GM factory specifications support. However, most of us builders even set up stock units with these specs that I am giving you.
2 - 4 Band clearance target: 0.060" ...Slightly more is okay (0.075'') Use the OEM Green Band
3 - 4 Clutch clearance target: 0.030" ...Slightly more is okay (0.045"). Use the OEM clutches with 4L65E H-D THICK apply and selective backing plates.
This clearances will give you the proper shift timings.
I would recommend installing a "Corvette" intermediate servo if the trans does not have one.
Install a new servo check-ball capsule. (If the trans is completely stock with no valve-body changes, then buy the Superior-Fairbanks version of the part).
Install a new sun-gear shell and gear if this unit is older than 2008 or if you see any ware.
Should the 2 - 4 Band be too lose and the 3 - 4 clutch be too tight; the 2 - 3 up-shift will not occur properly (basically what you found).
Also should the 2 - 4 band be too tight and the 3 - 4 clutch be too lose... the 2 - 3 shift will still not occur properly.
Incorrect timing of this shift will either cause a down-shift into first instead of third; or up-shift into fourth instead of third, before eventually going into third gear.
This is going to go against what the GM factory specifications support. However, most of us builders even set up stock units with these specs that I am giving you.
2 - 4 Band clearance target: 0.060" ...Slightly more is okay (0.075'') Use the OEM Green Band
3 - 4 Clutch clearance target: 0.030" ...Slightly more is okay (0.045"). Use the OEM clutches with 4L65E H-D THICK apply and selective backing plates.
This clearances will give you the proper shift timings.
I would recommend installing a "Corvette" intermediate servo if the trans does not have one.
Install a new servo check-ball capsule. (If the trans is completely stock with no valve-body changes, then buy the Superior-Fairbanks version of the part).
Install a new sun-gear shell and gear if this unit is older than 2008 or if you see any ware.
#4
The 2 - 3 and the 3 - 2 shifts in this unit are "syncronous shifts" and require proper clearances/ timings of the corresponding band and clutch assembly.
Should the 2 - 4 Band be too lose and the 3 - 4 clutch be too tight; the 2 - 3 up-shift will not occur properly (basically what you found).
Also should the 2 - 4 band be too tight and the 3 - 4 clutch be too lose... the 2 - 3 shift will still not occur properly.
Incorrect timing of this shift will either cause a down-shift into first instead of third; or up-shift into fourth instead of third, before eventually going into third gear.
This is going to go against what the GM factory specifications support. However, most of us builders even set up stock units with these specs that I am giving you.
2 - 4 Band clearance target: 0.060" ...Slightly more is okay (0.075'') Use the OEM Green Band
3 - 4 Clutch clearance target: 0.030" ...Slightly more is okay (0.045"). Use the OEM clutches with 4L65E H-D THICK apply and selective backing plates.
This clearances will give you the proper shift timings.
I would recommend installing a "Corvette" intermediate servo if the trans does not have one.
Install a new servo check-ball capsule. (If the trans is completely stock with no valve-body changes, then buy the Superior-Fairbanks version of the part).
Install a new sun-gear shell and gear if this unit is older than 2008 or if you see any ware.
Should the 2 - 4 Band be too lose and the 3 - 4 clutch be too tight; the 2 - 3 up-shift will not occur properly (basically what you found).
Also should the 2 - 4 band be too tight and the 3 - 4 clutch be too lose... the 2 - 3 shift will still not occur properly.
Incorrect timing of this shift will either cause a down-shift into first instead of third; or up-shift into fourth instead of third, before eventually going into third gear.
This is going to go against what the GM factory specifications support. However, most of us builders even set up stock units with these specs that I am giving you.
2 - 4 Band clearance target: 0.060" ...Slightly more is okay (0.075'') Use the OEM Green Band
3 - 4 Clutch clearance target: 0.030" ...Slightly more is okay (0.045"). Use the OEM clutches with 4L65E H-D THICK apply and selective backing plates.
This clearances will give you the proper shift timings.
I would recommend installing a "Corvette" intermediate servo if the trans does not have one.
Install a new servo check-ball capsule. (If the trans is completely stock with no valve-body changes, then buy the Superior-Fairbanks version of the part).
Install a new sun-gear shell and gear if this unit is older than 2008 or if you see any ware.
#6
TECH Junkie
Install the sonnax HD 2-3 shift valve and remove checkball #6
When shifting a 4l60e from 2nd to 3rd manually, lots is happening.
in 2nd, you have the forwards holding and the band holding
in D3 you have the band releasing via oil filling the "backside" of the servo and pushing-off the band, the 3/4 engaging, the forwards holding, AND the overruns applying. Having to apply the overruns at the same time as the 3rd accum (backside servo) oil volume is filled...the 3/4 clutch volume is filled...that's alot. The overruns just act like a 2nd accumulator. No bueno
However...before you go tearing into the trans and changing anything...explain better how it's not making the shift. Is it banging off the limiter...is it "flaring"...is it "bogging"
If you leave the shifter in OD position, will it make a WOT 2-3?
when you vac tested the valve body...you're saying it was ALL good? no issues at all? If so...it's been serviced before or you've found a unicorn
When shifting a 4l60e from 2nd to 3rd manually, lots is happening.
in 2nd, you have the forwards holding and the band holding
in D3 you have the band releasing via oil filling the "backside" of the servo and pushing-off the band, the 3/4 engaging, the forwards holding, AND the overruns applying. Having to apply the overruns at the same time as the 3rd accum (backside servo) oil volume is filled...the 3/4 clutch volume is filled...that's alot. The overruns just act like a 2nd accumulator. No bueno
However...before you go tearing into the trans and changing anything...explain better how it's not making the shift. Is it banging off the limiter...is it "flaring"...is it "bogging"
If you leave the shifter in OD position, will it make a WOT 2-3?
when you vac tested the valve body...you're saying it was ALL good? no issues at all? If so...it's been serviced before or you've found a unicorn
#7
Install the sonnax HD 2-3 shift valve and remove checkball #6
When shifting a 4l60e from 2nd to 3rd manually, lots is happening.
in 2nd, you have the forwards holding and the band holding
in D3 you have the band releasing via oil filling the "backside" of the servo and pushing-off the band, the 3/4 engaging, the forwards holding, AND the overruns applying. Having to apply the overruns at the same time as the 3rd accum (backside servo) oil volume is filled...the 3/4 clutch volume is filled...that's alot. The overruns just act like a 2nd accumulator. No bueno
However...before you go tearing into the trans and changing anything...explain better how it's not making the shift. Is it banging off the limiter...is it "flaring"...is it "bogging"
If you leave the shifter in OD position, will it make a WOT 2-3?
when you vac tested the valve body...you're saying it was ALL good? no issues at all? If so...it's been serviced before or you've found a unicorn
When shifting a 4l60e from 2nd to 3rd manually, lots is happening.
in 2nd, you have the forwards holding and the band holding
in D3 you have the band releasing via oil filling the "backside" of the servo and pushing-off the band, the 3/4 engaging, the forwards holding, AND the overruns applying. Having to apply the overruns at the same time as the 3rd accum (backside servo) oil volume is filled...the 3/4 clutch volume is filled...that's alot. The overruns just act like a 2nd accumulator. No bueno
However...before you go tearing into the trans and changing anything...explain better how it's not making the shift. Is it banging off the limiter...is it "flaring"...is it "bogging"
If you leave the shifter in OD position, will it make a WOT 2-3?
when you vac tested the valve body...you're saying it was ALL good? no issues at all? If so...it's been serviced before or you've found a unicorn
I don't know if the VB was serviced before, all pistons of the VB are stock size. when i said okay I meant they are not lower than the min recommended values by sonnax.
I do have the 2-3 HD upgrade by sonnax, if it is going to resolved the issue I will install it .... as I know it makes the over run clutches engaged all the time in OD or D1/2/3
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#8
TECH Junkie
It does not apply the overruns in OD shifter position.
Just D1/D2/D3
See my explanation above for how the overruns act like another accumulator during a 2-3 shift in stock form.
Since it's just hitting the limiter...not slipping or flaring...have you doublechecked with a log or scanner that the shift is being commanded?
Have you performed a pressure test...especially during the shift?
Just D1/D2/D3
See my explanation above for how the overruns act like another accumulator during a 2-3 shift in stock form.
Since it's just hitting the limiter...not slipping or flaring...have you doublechecked with a log or scanner that the shift is being commanded?
Have you performed a pressure test...especially during the shift?
#9
It does not apply the overruns in OD shifter position.
Just D1/D2/D3
See my explanation above for how the overruns act like another accumulator during a 2-3 shift in stock form.
Since it's just hitting the limiter...not slipping or flaring...have you doublechecked with a log or scanner that the shift is being commanded?
Have you performed a pressure test...especially during the shift?
Just D1/D2/D3
See my explanation above for how the overruns act like another accumulator during a 2-3 shift in stock form.
Since it's just hitting the limiter...not slipping or flaring...have you doublechecked with a log or scanner that the shift is being commanded?
Have you performed a pressure test...especially during the shift?
regarding the pressure test, do you mean the one done during assembly ?
Last edited by odd boy; 07-13-2019 at 12:34 AM.
#10
i do confirm that the car shifts normally at OD log is attached. I lowered the shifting point for testing only
however i am attaching logging files
however i am attaching logging files
Last edited by odd boy; 07-13-2019 at 05:24 AM.
#12
TECH Junkie
I'll have to look at the log later this evening. I don't have my tuning laptop with me at work today.
Post a tune file too if you can
Post a tune file too if you can
#14
TECH Addict
iTrader: (32)
3rd is a lil funky in a 60e setup. Usually has alot of delay before it completes the shift. 2nd not so bad.
What i do is set your max rpm rev limit for every gear to 7k. This will be under the Engine tab section.
In the trans section set your wot speed to stock settings. Or use gear wizard and let it auto adjust.
Set your commanded gear shift rpm to 6k. Thin see how it acts on a wot OD pull and report back.
U need to set the shift rpm early bc of the delay. Say u command 6k shift, it want actually make shift to 6800. Thts why i always set main max limiter to somthing high like 7k. Ive never had a car/truck bang the limiter before shift. They always need some head room. Hope this helps.
What i do is set your max rpm rev limit for every gear to 7k. This will be under the Engine tab section.
In the trans section set your wot speed to stock settings. Or use gear wizard and let it auto adjust.
Set your commanded gear shift rpm to 6k. Thin see how it acts on a wot OD pull and report back.
U need to set the shift rpm early bc of the delay. Say u command 6k shift, it want actually make shift to 6800. Thts why i always set main max limiter to somthing high like 7k. Ive never had a car/truck bang the limiter before shift. They always need some head room. Hope this helps.
#15
3rd is a lil funky in a 60e setup. Usually has alot of delay before it completes the shift. 2nd not so bad.
What i do is set your max rpm rev limit for every gear to 7k. This will be under the Engine tab section.
In the trans section set your wot speed to stock settings. Or use gear wizard and let it auto adjust.
Set your commanded gear shift rpm to 6k. Thin see how it acts on a wot OD pull and report back.
U need to set the shift rpm early bc of the delay. Say u command 6k shift, it want actually make shift to 6800. Thts why i always set main max limiter to somthing high like 7k. Ive never had a car/truck bang the limiter before shift. They always need some head room. Hope this helps.
What i do is set your max rpm rev limit for every gear to 7k. This will be under the Engine tab section.
In the trans section set your wot speed to stock settings. Or use gear wizard and let it auto adjust.
Set your commanded gear shift rpm to 6k. Thin see how it acts on a wot OD pull and report back.
U need to set the shift rpm early bc of the delay. Say u command 6k shift, it want actually make shift to 6800. Thts why i always set main max limiter to somthing high like 7k. Ive never had a car/truck bang the limiter before shift. They always need some head room. Hope this helps.
#16
TECH Junkie
odd boy, shoot me a pm
I forgot to look at these over the weekend. I'll try to take a peek at lunch
I forgot to look at these over the weekend. I'll try to take a peek at lunch
#17
TECH Junkie
Looking at the d3 and OD logs...you've got some funky stuff going on
In OD...3rd is being commanded at 47mph and 4450 rpm...but doesn't shift until 56mph and 5200 rpm. That's alot of delay
In D3 its being commanded at 63 mph. Your tunes have issues...the "normal" shift patterns 100% throttle mph should match the WOT tab mph.
But Once that shift is commanded...it should shift even in d3.
I would recommend using "bluecat's" shifting software to help you get the tune in the right spot.
But It appears as though the trans is very sluggish and not performing optimally either
In OD...3rd is being commanded at 47mph and 4450 rpm...but doesn't shift until 56mph and 5200 rpm. That's alot of delay
In D3 its being commanded at 63 mph. Your tunes have issues...the "normal" shift patterns 100% throttle mph should match the WOT tab mph.
But Once that shift is commanded...it should shift even in d3.
I would recommend using "bluecat's" shifting software to help you get the tune in the right spot.
But It appears as though the trans is very sluggish and not performing optimally either